This invention relates to radial piston hydrostatic transmissions and, more particularly, to a means of assuring a neutral transmission setting.
Radial piston hydrostatic transmissions are commonly used in the smaller variety of off-road vehicles such as small tractors. Unlike a conventional gear transmission which is positive engaging, a radial piston hydrostatic transmission is continuously engaged. As a result, the transmission control linkage assembly must be able to position a control ring within the hydrostatic transmission with greater precision in order to achieve a true neutral transmission mode. Such control linkage assemblies require frequent adjustment and are incapable of assuring a neutral transmission mode.
Another problem encountered by radial piston hydrostatic transmission occurs as a result of control ring creep. Once such transmissions are placed in a functional neutral mode, it is not uncommon for the transmission control ring to creep within the slack range of the control linkage assembly. Control ring creep represents the unintended transmission of power.